21534865018 has 16 divisors (see below), whose sum is σ = 32765731200. Its totient is φ = 10613033200.

The previous prime is 21534865007. The next prime is 21534865043. The reversal of 21534865018 is 81056843512.

It is a super-2 number, since 2×21534865018² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 600123 + ... + 634993.

It is an arithmetic number, because the mean of its divisors is an integer number (2047858200).

Almost surely, 2^21534865018 is an apocalyptic number.

21534865018 is a deficient number, since it is larger than the sum of its proper divisors (11230866182).

21534865018 is a wasteful number, since it uses less digits than its factorization.

21534865018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39293.

The product of its (nonzero) digits is 230400, while the sum is 43.

The spelling of 21534865018 in words is "twenty-one billion, five hundred thirty-four million, eight hundred sixty-five thousand, eighteen".